RE:RE:RE:Another update! Once again showing the bright future for targeted cancer therapies in previously hard to treat situations. Enhertus very clearly becoming the leader here. Two side notes - I see the lawsuit over IP between SeaGen and Daiichi Sankyo (Enhertu partner with AstraZeneca) hit a snag and looks like SeaGen was on the losing side. They may have to lay royalties for a few of their ADCs.
Secondly, Gilead had a solid update on their latest Trodelvy data for HR+HER- breast cancer (Tropics2 study). They met primary endpoint on progression free survival. It sounds like the response rate and survival are just close to Enhertus so the view is that while it's a win for Trodelvy, it may not lead to a lot of commercial activity in that indication.
So three wins for ADCs in cancers recently (Enhertu had another as well), showing the overall concept of using genetic markers to hone in on tumor targets is the hot area in oncology. Enhertus leading survival for HR+ is 6.4 months of PFS. So any new treatment in HR+ breast cancer that moves the progression free survival past 7 months would blow the market away.
THYX added HR+ as one of the new targets when they revamped the basket trial. By way of example, had the endometrial patient in the TH1902 dosage trial been an HR+ breast cancer patient, and gone the 33 weeks until they decided to return to a non-trial lifestyle, we would be looking at 8 to 9 months of progression free survival. Now that's a pure hypothetical, but if that had been the case, we would be looking at a platform that used taxol effectively and added a new standard of PFS greater than 7 months. Let's say she could have stayed on for 12 months. If so, TH1902 would blow away Enhertu for PFS. I'm just putting this out there to show how the bar on PFS is fairly low on these hard to treat cancers and we saw a tantalizing sign based on the fact the SORT1 target internalizing the drug allows for such a low safety signal treatment environment. Just what they theorized in the preclinical.
Let's hope one of the data points coming out of the basket trial is a few patients just plugging along with no new metastices or spread for long periods of time. That would set a new standard and be highly commercial,
qwerty22 wrote:
One interesting thing is the patient numbers fall in the middle of the range Paul talked about. So maybe his low and high estimates of the cost of the pivotal trial aren't so bad.
I started to look at the situation in late stage metastatic prostate cancer on the (wild at the moment) assumption that it could be their lead indication. From the (little) research I did I don't see the present approved drug situation being all that good for this cancer. Just my I'll-educated guess but I could see this indication as being another one where the fda might rush to get something approved if it shows some meaningful promise.
It seems true to me that some cancers offers pretty rapid paths based on serious unmet medical need while others have more options and so require less urgency from the regulators. It would be worth trying to gauge how each of the cancer indications THTX are chasing fit into this.
qwerty22 wrote:
If you want to dream of the fastest route to approval for TH1902 then this is a pretty good example. They didn't even make it to the end of the pivotal trial. They enrolled 152 patients. Approval came from interim analysis of 52 patients for efficacy and 101 patients for safety. The trial started in Nov 2020. The 57% ORR helps. A year and a half from start of pivotal trial to accelerated approval, amazing really.